Isolated Amazon Tribes Monitored with Space-Age Technology

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The vast jungles of the Amazon rainforest harbor tribes mostly
isolated from the outside world, whose way of life, largely
unchanged for millennia, is now increasingly threatened by
intrusions from modern civilization.

Now, scientists reveal they can monitor these " uncontacted
tribes " using satellites, which would allow safe, inexpensive
and noninvasive tracking of these tribes in order to protect them
from outside threats.

In order to help conserve these uncontacted Indians, researchers
need accurate estimates of their populations. One way to collect
this data involves flying over their villages, but such
overflights are both expensive and invasive, and could instill
fear among these indigenous peoples. Another strategy involves
encountering individuals on the ground, but among other risks,
scientists could
accidentally spread disease to members of the tribes.

Instead, scientists investigated whether satellite imaging could
monitor uncontacted tribes. "Since college some 15 years ago,
I've always been fascinated by these isolated tribes," said lead
study author Robert Walker, an anthropologist at the University
of Missouri at Columbia. "I've always wanted to study them in a
safe way, and remote sensing offers that."

The investigators focused on indigenous groups concentrated near
the headwaters of the Envira River, located at the border of
Brazil and Peru. These include the
Mashco-Piro, nomadic hunter-gatherers who live in Peru's
densely forested Madre de Dios region, and a number of
Pano-speaking farming societies.

The researchers combed through satellite images to look at five
isolated villages previously identified via overflights by
Brazilian officials. They confirmed these locations and measured
the sizes of their villages, houses and gardens. The villages
ranged from a small one of about 50 people to a large and growing
village of about 300 people.

"We can find
isolated villages with remote sensing and study them over
time," Walker told Live Science. "We can ask: Are they growing?
Do they move?"

Surprisingly, based on the sizes of the houses and villages, the
scientists find the population densities of these isolated
villages is about 10 times greater, on average, than other
villages of indigenous Brazilian peoples. This may be due to the
fact that they have to live closer together because they are not
as good at clearing the forest, since they lack steel machetes
and axes as well as modern devices like chainsaws and tractors,
the researchers said. The tribes may also be afraid of spreading
out due to fear of being attacked by outsiders, Walker said.

The researchers now plan to focus on 29 more isolated villages to
"look at their ecology — that is, elevation, distance from rivers
and roads — and use this to model where else we can find more
isolated villages," Walker said.

The scientists detailed their findings online today (Nov. 5) in
the journal Royal Society Open Science.